Yarn fluid treatment process and apparatus



Oct. 24, 1961 c. E. HALLDEN, JR, ETAL 3,005,251

YARN FLUID TREATMENT PROCESS AND APPARATUS Filed Dec. 19, 1958 2Sheets-Sheet 1 INVENTORS CARL EDWARD HALLDEN, JR. KAREL MURENBEELD BYMam ATTORNEY Oct. 24, 1961 c. E. HALLDEN, JR., ETAL 3,005,251

YARN FLUID TREATMENT PROCESS AND APPARATUS Filed Dec. 19, 1958 2Sheets-Sheet 2 F fg .5 Eig 6' lflg fl Q X 44 44 45 44 Z L 0 i RINVENTORS CARL EDWARD HALLDEN, JR.

KA REL MURENBEELD BY Cll wrs CZZA-WZM ATTORNEY United States Patent3,005,251 YARN FLUID TREATMENT PROCESS AND APPARATUS Carl EdwardHallden, Jr., Avondale, Pa., and Karel Murenbeeld, Wilmington, Del.,assignors to E. I. du

Pout de Nemours and Company, Wilmington, DeL, a

corporation of Delaware Filed Dec. 19, 1958, Ser. No. 781,549 13 Claims.(Cl. 28--1) This invention relates to a process and apparatus fortreating a bundle of filaments such as yarn or thread to produce amultifilament yarn of greatly increased tenacity and dyeabi'lity. Moreparticularly, the invention relates to a process and apparatus forproducing a bulky yarn composed of a plurality of individually crimpedfilaments having a random three-dimensional curvilinear configuration,high tenacity, and improved level dyeing characteristic and fasterdyeing rate.

Artificial fibers are normally produced most easily as continuousfilaments. These continuous filament yarns are very strong because ofthe absence of loose ends that are unable to transmit imposed stresses.Their extreme uniformity and lack of discontinuity, however, makesconventional continuous filament yarns much more dense than yarns madefrom staple fibers. The production of .yarn from staple fibers, however,is time-consuming and requires a complex series of operations to crimpthe fibers, align the fibers into an elongated bundle and then to drawthe bundle to successively smaller diameters. The final spinningoperation, which involves a high degree of twist, finally binds thesediscontinuous fibers together to produce a coherent yarn withconsiderably increased bulk. The occluded air spaces give them alightness, covering power, and warmth-giving bulk not normally possibleWith continuous filament yarns. Thus, to get staple fibers that can beprocessed on conventional wool or cotton spinning equipment, it has beenthe practice to cut continuous filament yarns such as rayon, acetate,nylon, as well as the polyacrylic and polyester fibers into shortlengths for spinning into staple yarn.

Recent developments in the textile industry have provided useful routesfor imp-roving the bulk and covering power and recoverable elongation ofcontinuous filament yarns without resorting to the staple spinningsystems of the prior art. A well-known process for making stretch yarninvolves the steps of twisting, heat-setting and then backtwisting to alow final twist level. Another yarn of improved bulk is preparedcorrnnercially by the steps of twisting, heat-setting and backtwistingon-the-run using a false-twisting apparatus. This end product can befurther modified by hot relaxing to improve the bulk and handle. Stillanother bulk yarn is being prepared by the well-known staffer boxtechnique wherein the yarn is steamed to heat-set while it is in acompressed state in the stufi'er box. 1

All of these yarns'of the prior art are produced by a process which hasthe common elements of deforming the yarn mechanically and'thenheat-setting either with or without an after-relaxation step. It was notuntil the recenly disclosed product in US. 2,783,609 to Breen and itsprocess of manufacture became known that an entirely new techniquebecame available for improving the bulk of continuous filament yarns.This technique involves exposing a filamentary material to a rapidlymoving turbulent fiuid, thereby inducing a multitude of crunodalfilament loops at random intervals along the individual filaments. Theseloops and snarls of entangled loops increase the bulk of the continuousfilament yarns considerably and result in fabricsof improved cover,bulk, handle,

and the like. With the invention of Breen, a new tool is available forthe bulking o-f filamentary structures, i.e., a turbulent fluid. Fluids,of course, have been used for yarn treating in many of the prior artoperations such as drying, extracting, transporting, and the like. Untilthe invention of Breen, however, they had not been used to entangle,convolute, and bulk a filamentary material. It has now been discovered,however, that a new process utilizing the turbulent fluid techniqueresults in new yarn products that have certain unique properties notheretofore disclosed in the art.

It is an object of the present invention, therefore, to providecontinuous filaments and continuous filament yarn having a bulkinessgreater than staple yarn spun from comparable fibers. Another object isto provide multifilament yarn resembling spun staple in its desirablelightness, covering effectiveness and warmth-giving bulk but retainingthe characteristic continuous filament freedom from loose ends,fuzziness, and pilling. It is also an object to prepare a bulkyfilamentary material especially useful for the pile component of pilefabrics. It is another object to provide both crimped and uncrimpedsynthetic organic filamentary strands having high tenacity and anunusually high rate of dyeability. It is another object to provideapparatus which is peculiarly suited ior carrying out theabove-described procms and producing the above-described products. Otherobjects Will appear hereinbelow.

According to this invention there is provided synthetic organicfilamentary strands having high. tenacity and a rate of dyeability whichhas not been attained heretofore. These products are produced by feedinga synthetic organic filamentary strand at an overfeed of at least about12% to a plasticizing stream of a compressible fluid in which theindividual filaments, while in a plastic state, are momentarilyseparated from each other and then cooled. The strand may be cooled bypassing through air at nor mal room temperature. The product has hightenacity and also possesses a rate of dyeability at least about greaterthan that of the feed strand. By increasing the overfeed to at least30%, preferably at least 40%, the filamentary product produced contains,in addition to the high tenacity and high rate of dyeability set forthabove, fibers possessing an independent random, persistant,threedimensional non-helical curvilinear configuration along the line ofthe filamentary strand and is substantially free of stable crunodalloops.

The process and apparatus of this invention represent a substantialimprovement over known methods and equipment for bulking yarn not onlybecause of the superior quality of the products produced, but alsobecause of the high rate of production which the process and apparatusmakes possible. The invention and the manner of carrying it out will bemore clearly understood by reference to the drawings in which,

FIGURE 1 is a sectional view of a preferred embodiment of the apparatusof this invention.

FIGURE 2 is a perspective view of the apparatus of FIGURE 1.

FIGURE 3 is a sectional view of a preferred embodiment of the supplyportion 6 of the apparatus of FIG- URE 1.

FIGURE 4 is a perspective view of the apparatus of FIGURE 3.

FIGURES 5 and 6 are sectional views of alternate apparatus which may beutilized in this invention.

FIGURE 7 is an exploded View of an apparatus suitable for handling anumber of individual yarn ends simultaneously. i

FIGURE 8 is another embodiment of such an apparatus for handlingmultiple yarn ends in the form of a warp sheet or the like.

FIGURE 9 illustrates another useful embodiment of the apparatus.

In FIGURE 1 the treating apparatus includes a housing formed of a lowersection 6 and an upper section 7. The yarn enters preheating assembly 10and then passes through the yarn introducing means 11 in housing section6 to bulking chamber 15 in the shape of a cone having housing section 6as a base, the conical surface being formed in upper housing section 7.Yarn introducing means 11 is slightly larger in diameter than thegreatest diameter of the strand to beprocessed to avoid substantialimpedance of yarn'movement A fluid plasticizing medium enters "chamber15 at high velocity (at least V2 sonic) from a suitable manifold 12through the fluid injection passage 13 in lower housing 6 and forces therapidly moving threadline out of its original path so that both impingeagainst the side of chamber 15. The filamentary material is then removedthrough the Venturi throat 16 in upper housing 7 along with fluid. Thetreated yarn after issuing from the Venturi throat at 16 is forwarded at"a controlled rate to a windup.

In FIGURE 2 yarn is shown being fed to preheating assembly 10 by feedrolls and a pigtail guide while fluid enters manifold 12. Yarn product 8is withdrawn by advancing rolls from fluid exhaust 9. This apparatus isat least 50% more eflicient thanprior known apparatus for heating yarnwith fluids as allowing a much higher rate of processing withoutreducing yarn product quality.

A preferred embodiment of the apparatus of this invention is shown inFIGURES 3 and 4. These views show the relative positioning of anauxiliary baflie 18 which is inclined over the exit of the fluidinjection passage 13 and yarn introducing passage 11. This baffleconcentrates the fluid plasticizing stream on the yarn bundleimmediately at the point of entry of both into treating chamber 15 andsubstantially improves the efficiency of heat and energy transfer fromthe fluid to the yarn bundle. The process of this invention is about 50%more efficient than the apparatus of FIGURE 1 without baifie 1S.

FIGURES and '6 are alternative embodiments of apparatus suitable for theprocess of this invention. Fluid passageway 49 and yarn passageway 41,respectively, terminate in chamber 42 and impinge on solid surface 44under the driving force of the fluid medium. Venturi outlet 43 may bepositioned as shown or in any suitable alternate position relative topassageways 40 and 4 1 but will generally be as shown. The treatingchamber wall or other obstacle surface can also have varied positions asshown by these figures and dotted line 45. Other possibilities of angledwalls and treating chamber shapes will be obvious to those skilled inthe art. l FIGURE 7 shows a species of apparatus suitable for thehandling of multiple ends of yarn and contains the same elements shownin FIGURE 1 with some slight modifications for ease of fabrication,string-up, and multiple end operation. Steam enters body 34 throughmanifold 31 and is distributed to a plurality of fluid injectionpassageways 33 through suitable distribution means. Yarn is introducedby suitable means through yarn passageways 32 into a common treatingchamber contained in block '35. The individual ends of crimped yarn thenpass through the Venturi outlets-'38 located in head 36.

FIGURE 8 shows another form of Venturi unit that can be used in place ofblock 35 in FIGURE 7 above. This modification has certain advantageswith reference to ease of string-up when processing multiple ends ofyarn in the form of a warp sheet or thelike through the fluid jets ofthis invention. The fluid injection and yarn passageways can also beslots rather than the individual elements shown at 32 and 33 in FIGURE7.

In FIGURE 9 fluid inlet 40 surrounds yarn inlet 41 but the latter iseccentric in the fluid inlet so that pressure against incoming yarn-byjetting'fluid-is not uniform and the yarn is diverted from its normal'path by the unbalanced :force on the yarn and forced to impinge againstthe wall 44 of treating chamber 42. Similarly, *both yarn and fluidmaybe introduced into the chamber concurrently from a single tubularinlet so long as it is forced to impinge upon a suitable obstaclesurface within the treating chamber, preferably one inclined directly inthe path of the incoming yarnsand fluid so that the direction of theyarn and'fluid is changedthereby prior to exiting from the treatingchamber by a conical or venturi shaped outlet.

In a preferred embodiment of this invention a plasticizing fluid at highvelocity is directed against a moving filamentary strand so that theyarn is forced against a solid obstacle which abruptly changes thedirection of movement of both the strand and the fluid. The strand isthen removed from the treating chamber by the moving fluid while thelatter undergoes a controlled gradual expansion. At overfeeds of between12% and about 30% the product is uncrimped but still possesses theastonishingly high dyeability rate and tenacity characteristics of thecrimped :product. At strand overfeeds of at least about 30% theplasticizing fluid softens the filamentary material, furnishes theenergy necessary to accomplish filament crimping, as well as removingthe crimped product from the treating chamber. While removing thiscrimped product, the treating fluid undergoes a controlled gradualexpansion which serves the auxiliary purpose of initiating cooling ofthe product and reducing fluid velocity, thereby eliminating unduetension on the yarn. This controlled expansion of the plasticizing fluidas it leaves the treating chamber is preferably accomplished by passingboth strand and fluid through a conical or vent-uri section, although asuitable baflle may sometimes be used. This conical section (frustum),which, of course, has its widest end downstream, has a taper between 3and 45 with the preferred limits of 5 and 15". As shown in FIGURE 1, theyarn to be treated is usually fed at a controlled rate as may bedetermined by the rolls between which it passes on its way into the jet.Details of the processing conditions are disclosed in copendingapplication Serial Nos. 698,103, filed November 22, 1957, and 772,- 475,filed November 7, "1958, now abandoned, by Breen and Lauterbach.

The process and apparatus of this invention can be used to crimp andbulk any natural or synthetic plasticizable filamentary material.Thermaplastic materials such as polyamides, erg poly(epsiloncaproamide), poly(hexamethylene adipamide); cellulose esters;polyesters, e.g., polyethylene terephtha-late, poly(hexahydrop-xylyleneterephthalate), etc.; polyvinyls and polyacrylics, e.g., polyethylene.and polyacrylonitrile, as well as copolymers thereof can be crimped togive the threedimensional, random, curvilinear configuration describedherein. While the preferred form of material is continuous filaments,the process and resultant improvements occur with staple yarns as well.Both types of materials can be made into bulky yarns and fabrics havingimproved bulk, covering .power (opacity) and hand.

This apparatus andprocess are useful for both monofilament yarns intextile deniers as well as the heavier carpet and industrial yarn sizeseither singly or combined in the form of a heavy tow. Fine count andheavy count staple yarns can be processed both singles and plied. The.process and product are also not restricted in the case of thesynthetic materials to any one particular type of filament crosssection. Cruciform, Y- shaped, deltashaped, ribbon, and dumbbellandother such filamentarycross sections can be processed at least aswell as round filaments and usually contribute still more bulk than isobtained with round filaments. By proper design of the jet and process,multiple ends of yarn may be handled either in the form of warp sheets,ribbons, or tows.

The turbulent fluid used .to treat the filamentary material may beair,steam, orany-other compressible fluid or vapor capable of plasticizingaction on the yarn proa vided that it has a temperature above thesecond-order transition temperature of the filament. Preferably thetemperature is above 300 F. Hot air will give suflicient plasticizationin the turbulent region for many fibers although it may be desirable forcertain fibers to supplement the temperature effect with an auxiliaryplasticizing medium. Actually, steam is preferentially used in thesubject process since it is a cheap and convenient source of a highpressure fluid with a compound plasticizing action.

The temperature of the fluid medium must be regulated so that the yarntemperatures do not reach the melting point of the fiber. However, withfibers made from fusible polymers, the most effective bulking and thegreatest productivity is obtained when the temperature of the turbulentfluid is above the melting point of the fiber. In this case the yarnspeeds should be great enough so that melting does not occur. Because ofthe great turbulence and the high heat, yarns are heated rapidly.Temperatures lower than the second-order transition temperature (T,;) ofthe yarn material should usually not be employed because under theseconditions any crimping or bulking of the filaments is not perma nentand utility of the fibers is reduced.

The process usually operates at temperatures in excess of the melting ordegradation temperature of the yarn being treated, especially at highrates of yarn throughput. The threadline during string-up should be keptmoving at a rate approximate to that achieved in operation. There are anumber of suitable means for achieving this string-up on-the-run-one ofthe simplest being the use of a sucker gun to start the yarn through thejets. Preferably, as shown in FIGURE 2, yarn is removed abruptly fromthe plasticizing fluid as it leaves the apparatus.

For high speed operation, it is frequently desirable to preheat the yarnbundle prior to its entry into the treating chamber of the subjectinvention. This preheating can be accomplished by any number of means,one of the simplest being that shown in FIGURES 1 and 2. Here some ofthe fluid plasticizing medium is diverted through passageway 14 into theyarn preheater where it passes in a direction countercurrent to the yarnbundle and effectively preheats the yarn to minimize the heat loadrequirements in trating chamber 15. Other forms of preheaters can takethe form of heated rolls, hot plates, infrared radiation, and manyothers commonly known in the art. Either post heating or post coolingcan be utilized on the yarn immediately after it emerges from theventuri to modify, or improve the crimped and convoluted configurationof the filaments in the yarn bundle. Use of preheating, precooling, or acombination depends on the physical characteristics and fiber morphologyof the filamentary material being treated, as well as the finishedproduct desired.

The configuration and accompanying characteristics of yarn treated bythe apparatus of this invention depend in part upon the amount andvelocity 'of the fluid plasticizing medium, the various features of thejet construction, temperature, yarn speed, and the fiber being treated.A further description of the products that can be prepared using thesubject apparatus as well as alternative processes are described incopending application Serial No. 698,103, filed November 22, 1957, byBreen and Lauterbach. The desirable bulkiness and other attributes ofyarns as treated herein are discussed in the above application.

It is desirable to have the various yarn passageways made of especiallyhard material to reduce wear. These yarn passageways may be made ofhigh-carbon steel of great hardness while the remainder of the housingmay be of softer material such as ordinary stainless steels or evenbrass. It may be desirable for the passageways to carry hardened insertsbecause of the wear potential from abrasion by the filamentary bundle.There are a number G of suitable ceramic materials available on themarket for this purpose.

For the optimum bulking of specific yarns, the jet parameters have to becarefully determined. The size of the yarn hole 11 as well as that ofthe venturi exit 16 (see FIGURE 1) depends upon the type and denier ofyarn that is to be processed. The yarn introducing tube at 11 should bejust large enough to allow passage of the yarn being treated. The exitat 16 must be large enough to allow the crimped yarn to exit withoutimposing excess tension on the yarn bundle as well as the passage of theplasticizing fluid itself from the treating chamber. The plasticizingfluid inlet 13 has to be of suflicient size to deliver an adequateamount of plasticizing fluid. The length to diameter ratio of the fluidinlet is important since the low ratios which are preferred have aconsiderable beneficial influence upon the force distribution to theyarn bundle. For high efliciency it is preferred that any gap betweenthe yarn and the fluid introducing passageway be kept as small aspossible.

In the embodiment shown in FIGURE 1, the angle adpha in the treatingchamber 15 is critical. The chamber is preferably in the form of a rightcircular cone and the angle alpha may vary from 60 to 120 depending uponthe specific design of treating apparatus and material being. treated.In a preferred species this angle is 90:10.

Another important variable of the above embodiment of the yarn treatingapparatus is the angle beta between the axis of the yarn introducingmeans 11 and the axis of fluid passage 15. The angle beta can be varied,depending upon characteristics desired in the process and product, from20 to 70 with a preferred range from 25 to 45. In the preferred speciesof the apparatus the yarn introducing and the fluid passageway will haveaxes in the same plane. This achieves maximum effectiveness in applyingthe kinetic force of the treating fluid to the moving threadline. Whenthe fluid passageway is off-center in circular jets, some torque actionmay result. In noncircular jets, excessive turbulence may result and/orineflicient transfer of kinetic and heat energy to the moving threadlinemay occur. The treating chamber is preferably in the shape of a cone asindicated in FIGURE 1 but may be any other suitable configuration suchas spherical, cubic, tetrahydral, octahedral, etc., and generally theaverage height of the treating chamber should not be substantially lessthan about one-third of the average width. Perferably, the treatingchamber will have a volume between about 1 and about 10 times that of asphere having a diameter equal to the sum of the diameters (or theequivalent) of the yarn and fluid inlets at the point of interception ofthese inlets with the treating chamber. The treating chamber should havesufficient volume to allow the yarn to momentarily accumulate withoutexcessive crowding upon an obstacle surface within the treating chamberprior to being withdrawn.

The following example illustrates operation of the apparatus in theprocess of this invention.

Example 1 A 1020 denier/ 68 filament yarn of polyhexamethylene adipamideis processed using a device similar to that shown in FIGURE 1. The yarnfeed speed is 400 y.p.m. and the take-up speed is 222 y.p.m. to give aneffective over-feed, based on feed speed, of The plasticizing fluid issteam at a temperature of 550 F. and a pressure of psi. Steamconsumption at this rate of yarn processing is approximately 20 lbs./hr.The crimped yarn product is characterized by a random three-dimensionalcurvilinear crimp of the type described in copending application SerialNo. 698,103, filed November 22, 1957, by Breen and Lauterbach, and isparticularly useful as a mg or pile yarn. The amplitude, permanence, andnumber of crimps per unit of length in the filaments make the yarnparticularly suitable for this purpose.

The claimed invention:

A a css for m ar n to a yntheti nea P 1 m r a tran q sab l a e a e s 75%reate than that of the starting material, comprising continuouslyfeeding the strand intg a treating chamber in a direction pasein'g'across an obstacle surface within the chamber, let in a s zins S e m ofw Pm bk u a n etsm sretu s o a least 00 at h velocity i t? t e chamb eress i st nd feed direction at n angle of at least 20 to change thedirection of movetn f he st and tew r h ac e Surface, m n ing the stranda plastic state against the obstacle surface to, provide an abruptchange in the latter direction of movement of the strand and adjacentfluid, conductin the tra d and u d m the Chamber, the t n being removedat a rate less than the feed rate to provide an overfeed of at least12%, quenching the strand while imulta eqi sly mendi a reducing thevelocity of the adjacent fluid, removing the strand from the fluid, andwinding it on a package. i

The process of claim 1 in which the fluid is steam.

3. The prqeess of claim 2 in which the strand and steam after abruptlychanging direction are passed concurrently through a strand quenchingzone in which the steam is cqoled by gradual expansion.

' 4. The process'of claim 2 in which the steam is jetted against thepolymeric strand at a velocity of at least /2 sonic velocity.

5. The prqcess of claim 2 in which the strand-is fed and removed atrates which provide an overfeed of at ea t 30 v to t e sat ns ha be 6.Yarn treating apparatus comprising a housing forming the wall srof atreating chamber, an obstacle surface within said chamber, yarn inletmeans for feeding yarn into the chamber along an axis which is at aconverging angle to said obstacle surface, fluid inlet means for jettinga compressible fluid into the chamber at high velocity aleng an axiscrossing said axis of the yarn inlet means at an angle of at least 20and directed against the obstacle surface, and tubular exit means forc'ondueting both yarn and fluid from the chamber, said exit means havinga reduced cross sectional area relative to that of the ehaniber and anincreasing cross-sectional area towards the exterior end to provide acontrolled gradual expansion of fluid exiting from the chamber.

7. The apparatus of claim 6 in which the treating ehamber has a volumebetween about 1 and about times that of a sphere having a diameter equalto the sum of the diameters of the yarn and fluid inlet means at thepaint of interception of these inlet means with the treating chamber.

8. The apparatus of claim 7 in which the treating chamber is a frustumof a conical surface having an apex angle of between about 60 and about120.

9. The apparatus of claim 8 in which the apex angle is between about 80and about 100 and the frusturn has a height of not more than 1 times thediameter of the base.

10. The apparatus of claim 8 in which the axes of the yarn inlet meansand fluid inlet means intersect Within the chamber at a point spacedfrom the terminus of the fluid inlet means by a distance less than timesthe diameter of the fluid inlet means at said terminus.

11. The apparatus of claim 10 in which the angle formed by the axes ofthe yarn and fluid inlet means" is between about and about 12. Yarntreating apparatus of claim 8 containing a deflecting member positionedwithin the chamber at the fluid inlet means terminus to direct incomingfluid toward the obstacle surface.

13. Yarn treating apparatus comprising a housing con: taining a treatingchamber in the form of a frustum of a right conical surface having anapex angle of between about and about a tubular exit from the. chambertapering divergently toward the exterior, the inner end of the tubularexit coinciding with the smaller base of the frustum; an entranceway forintroducing yarn into the treating chamber and having a terminus'in thelarger base of the frustum and having a common axis with the conicalsurface and the tubular exit; an entranceway for introducing fluid intothe treating chamber and having an inner terminus in the larger base ofthe frustum at a location in said base adjacent to the yarn entranceway,the axis of the entranceway for fluid forming an angle of between about25 and about 45 with the axis of the yarn entranceway.

References Cited in the file of this patent UNITED STATES PATENTS

1. A PROCESS FOR IMPARTING TO A SYNTHETIC LINEAR POLYMERIC STRAND ADYEABILITY RATE AT LEAST 75% GREATER THAN THAT OF THE STARTING MATERIAL,COMPRISING CONTINUOUSLY FEEDING THE STRAND INTO A TREATING CHAMBER IN ADIRECTION PASSING ACROSS AN OBSTACLE SURFACE WITHIN THE CHAMBER, JETTINGA PLASTICIZING STREAM OF COMPRESSIBLE FLUID HAVING A TEMPERATURE OF ATLEAST 300*F. AT HIGHT VELOCITY INTO THE CHAMBER ACROSS SAID STRAND FEEDDIRECTION AT AN ANGLE OF AT LEAST 20* TO CHANGE THE DIRECTION OFMOVEMENT OF THE STRAND TOWARD THE OBSTACLE SURFACE, IMPING-